Brake Caliper Locking Assembly for Pad Clearance and Vibration Damping
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Solution Overview
Problem
Existing air-actuated heavy-vehicle disc brakes suffer from unintentional contact between brake pads and the rotor due to unevenness or engine vibration, leading to reduced efficiency, increased wear, and higher fuel consumption, and existing positive pad retraction systems fail to account for differential wear and are difficult to align.
Innovation Solution
A brake assembly with a caliper and brake carrier featuring a lock arrangement that inhibits relative sliding between the caliper and brake carrier, using an expandable element or moveable wedge to maintain a desired clearance and dampen vibrations, with the expandable element being operated by a gas or liquid introduction into a cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the caliper is allowed to slide freely on guide pins relative to the brake carrier, then the brake pads can move to contact the rotor during braking operation, but the brake pads may contact the rotor unintentionally outside braking operation due to vibration or cornering forces
Solution Approach 1:
The guide pin is designed with a resilient portion that allows dynamic adjustment between two states: a first state during braking where the caliper can slide freely to engage the rotor, and a second state during normal operation where the resilient portion engages with a stop surface to prevent unwanted movement and maintain clearance. This dynamic mechanism automatically adapts to operational conditions without external control.
Solution Approach 2:
The guide pin is segmented into distinct functional portions: a resilient portion that can deform elastically, a rigid portion that provides structural support, and a stop surface that defines the retracted position. This segmentation allows each portion to perform its specific function independently, enabling the guide pin to both allow movement during braking and prevent movement during normal operation.
2Reliability
If existing positive pad retraction systems are used to push brake pads away from the rotor, then pad clearance is maintained, but the systems cannot account for differential wear between inboard and outboard brake pads and rotor surfaces
Solution Approach 1:
The resilient guide pin serves multiple functions simultaneously: it acts as a retraction mechanism to maintain pad clearance, provides wear compensation for both inboard and outboard pads, dampens vibrations, and allows free movement during braking. This multi-functional design eliminates the need for separate positive pad retraction systems while addressing differential wear through the natural elasticity of the guide pin.
Solution Approach 2:
The resilient guide pin automatically compensates for differential wear between inboard and outboard brake pads and rotor surfaces through its elastic deformation. As wear occurs, the guide pin naturally adjusts its deflection to maintain proper clearance without requiring external adjustment mechanisms or sensing systems, making the system self-regulating.
3Reliability
If existing positive pad retraction systems are used to ensure pad retraction, then clearance is maintained, but the systems are difficult to align and locate due to machining tolerances
Solution Approach 1:
The guide pin utilizes elastic deformation as its primary mechanism, changing from a rigid positioning element to a flexible one that can accommodate machining tolerances. The resilient portion's ability to deform elastically allows it to absorb dimensional variations and misalignments that would be problematic for rigid positive retraction systems, significantly simplifying manufacturing and assembly requirements.
4Reliability
If the guide pin is made rigid to prevent unwanted movement, then pad clearance is maintained, but the brake assembly produces rattling sounds due to guide pin abutting against the caliper during vibration
Solution Approach 1:
The guide pin is designed with non-uniform properties along its length: the resilient portion has reduced stiffness to absorb vibrations and prevent rattling, while the rigid portion maintains sufficient stiffness to provide structural support and maintain clearance. This localized variation in mechanical properties allows the guide pin to simultaneously dampen vibrations and maintain reliable pad retraction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents unintentional contact between brake pads and rotor, reduces wear, and enhances vehicle efficiency by maintaining consistent pad-to-rotor clearance and damping vibrations, while requiring a compact design and minimal additional components.
Implementation Method 1
The first lock arrangement may be configured to increase a frictional force between the first lock arrangement and the other of the caliper or the first guide pin in a first state of the first lock arrangement relative to a second state of the first lock arrangement
Implementation Method 2
The expandable element may be transformed between the contracted configuration and the expanded configuration via the introduction or removal of a gas or a liquid into said cavity
Implementation Method 3
the lock arrangement may also act to dampen undesirable vibrational effects, such as a rattling sound caused by the guide pin abutting against the caliper due to engine vibration for example
Data Source
AI summary
A brake assembly including a caliper that has a first guide bore, a brake carrier arranged to receive a brake pad, a first guide pin secured to the brake carrier, and a first lock arrangement. The first lock arrangement is operable to selectively inhibit relative sliding between the caliper and the brake carrier.